Drill sharpening apparatus



April 19, 1960 F. H ZACHOW DRILL SHARPENING APPARATUS Filed 001;. 11,1956 5 2 n W ,T m 0 h HUN... 1 c H m mo :59 2 m k W, n m E F 02 M 4 mUnited States Patent DRILL SHARPENING APPARATUS Frank Henry Zachow,Tacoma, Wash.

Application October 11, 1956, Serial No. 615,325

3 Claims. (Cl. 51-125) This invention relates to drill sharpeningapparatus of the class designed for use in sharpening twist drills withemery wheels or other abrasive members.

. It is the general object of this invention to provide drill sharpeningapparatus for sharpening drills of various sizes efliciently andaccurately.

. It is another object of the present invention to provide drillsharpening apparatus which sharpens the drill symmetrically.

Still another object of the present invention is the provision of drillsharpening apparatus which by a simple adjustment can be used forgrinding the angular cutting edge in the desired position on the drill.

Still a further object of the present invention is the provision ofdrill sharpening apparatus which advances the drill toward thesharpening stone to a predetermined point where its forward motion isarrested positively.

Still another object of this invention is the provision of drillsharpening apparatus which makes possible clear obeservation of thedrill .at all times while it is being sharpened. Another object of thisinvention is the provision of drill sharpening apparatus which is ofsimple inexpensive construction, which is safe and easy to use, andwhich is adapted for use in home workshops as well as in industrialestablishments.

The manner in which the foregoing and further objects of this inventionare accomplished will be apparent from the accompanying specificationand claims considered together with the drawings wherein:

Fig. 1 is a plan view of the herein described drill sharpeningapparatus;

Fig. 2 is a view in front elevation looking along line 2-2 of Fig. 1;

Fig. 3 is a view in side elevation of the presently described drillsharpening apparatus; and

Fig. 4 is a sectional view taken along line 4--4 of Fig. 3 andillustrating the manner of mounting the apparatus.

Generally stated the drill sharpening apparatus of my invention includesa base and guide means directed toward an abrasive member against whichthe drill is to be sharpened, the guide means mounting the base forreciprocative movement toward and away from the abrasive member. Stopmeans are provided for controlling and limiting the forward movement ofthe base.

A bed is mounted on the base at a predetemined angle with respect to theabrasive member. Drill holding means are seated in the bed alternatelyin upright and inverted positions for contacting in turn the respectivecutting faces of the drill with the abrasive member.

Considering the foregoing in greater detail and with particularreference to the drawings:

The herein described apparatus is mounted on a base member which mayconveniently comprise a block of wood of suitable dimensions cut away toform a recess 11. The base member in turn is mounted on guide means forlongitudinal reciprocation with respect to an abrasive member such asthe emery wheel 12.,

In the illustrated embodiment, the guide means comprises a track member14 formed with. a longitudinal groove or track 16 and a longitudinalpassageway 18 which affords clearance for the other elements of theassembly, as will be apparent hereinafter. The track is aligned with theaxis of wheel 12 and is afiixed to a work bench or other rigidstructural member by suitable means such as screws 20.

The under surface of base 10 is formed with guide strip 22. The meetingsurfaces of base 10 and member 14 may be polished for sliding engagementso that the base may be moved easily back and forth toward and away fromemery wheel 12, being guided by strip 22 in track 16.

In order to sharpen the drill symmetrically, means are present forcontrolling the advancement of base member 10 and for stopping it at apredetermined point. Such means in the illustrated form comprises a cam24 keyed to a rotatable shaft 26 and actuatable by a knurled wheel 28which also is keyed to the shaft.

Cam 24 has a spiral shaped peripheral surface 30 and is positioned withrespect to a stop member 34, which is rigid to stationary track 14, insuch a manner that as the cam is turned in a counterclockwise directionthe cam surface engages the side surface of stop 34-, which accordinglyacts as a cam follower. This makes possible the controlled advancementof base member iii in the direction of emery wheel 12. When the operatorpushes base 10 forwardly in his right hand while simultaneously turningknob 28 in a counterclockwise direction to his left, the base may beadvanced until the drill surface just touches the side surface of theemery wheel and is ground sufiiciently to sharpen it. Thereup-on itsadvancement is stopped.

For mounting the drill on the base 10 there is provided a bed which liesobliquely at a predetermined angle with respect to the working surfaceof emery wheel 12. This bed may comprise a pair of oppositely disposedangle irons 36, 38 suitably fastened to the base member 10, as by meansof screws 40. The side edge of at least one of the angle irons, forexample angle iron 38, is bent inwardlysubstantially at right angles toform a retaining tab 42.

The means employed for holding the drill 44 to be sharpened include apair of plates 46, 48. These plates are adapted to seat in the bedfastened to base 10 and are formed with opposed ribs 50, 52 dimensionedt) receive the' drill.

Clamping means are present to clamp the drill between the plates,thereby holding it securely in place during the sharpening operation. Inthe embodiment illustrated particularly in Fig. 2, the clamping meanscomprises a yoke-shaped member including side segments 54, 56' andconnecting segment 58. The side segments are dimensioned to be receivedin cutaway portions of top plate 46. Also, their lower portions areformed with inwardly turned extensions 60:, 62 which project below theplane of the bottom surface of lower plate 48. Accordingly, when theplates are seated in the retaining bed, they are locked against movementin one horizontal direction by the forwardly projecting tab 42, whichengages the front surface of side segment 56, and in the oppositedirection by the inwardly turned extensions 60, 62, which engage theends of angle irons 36, 38, respectively.

The clamping assembly is completed by a screw 64 the bottom end of whichis secured to top plate 46 and the stem of which is threaded through agrooved nut 66 which penetrates a perforation through connecting segment58. Hence turning nut 66 raises or lowers top plate 46.

The operation of the herein described drill sharpening apparatus is asfollows.

A drill to be sharpened is placed between plates 46, 48 where it'nestsin the recess formed in part, by opposed ribs 50, 52. The drill isadjusted by rotation until its cuttingsurface is at the desired anglewith respect to theside face of emery wheel, 12; Nut 66', is tightened,thereby clamping the drill between plates 46', 48 The drill and" itsholding assembly next are seated in the. bed formed by angle irons 36,38; being restrained against horizontal movement by tab 42 andextensions 60, 62..

The right hand of the operator is placed on base member and-his lefthand'on knurled nut 28. The base member and the drill; mounted thereonthen arepushed forwardly in the direction of; the emery wheel until camsurface 30'of cam 24 is in contact 'with the side edge of stop member34. V I

The operatorexerts continuous, pressure on base member 10 and 'at thesame time turns knurled nut-28 in a counterclockwise. direction, therebyalso turningcam 24 V and permitting forward movement of the assembly ata at whichit is'turn ed.

The assembly is advanced in this manner until the rate determined by thecontour of the cam and the rate drill touches the emery wheel and' hasbeen sharpenedrotatedithrough 180, and the holder again nested in thehad formed by angle irons 36, 38. This presents the opposite workingsurface of the drill to the emery wheel. Theassembly is then advancedtoward the emery wheel without changing the cam setting until the camengages stop 34. The opposite working surface of the drill there uponwill be ground symmetrically with the surface ground first. v

Accordingly it will be apparent that by the present invention I'haveprovided drill sharpening apparatus by means of which drills can besharpened symmetrically, easily, and rapidly. In addition, drills of anyof the conventional sizes can be sharpened in the same apparatus, andthe cutting edge can be ground into the drill at desired positions.Also, the operator can observe the progress of the sharpening operationwithout hazard.

member, a base, guide means directed towardthe abrasive member andmounting the base for straight line Eeed movement toward said abrasivemember, bed means mounted on the base at a predetermined anglewithrespect to the abrasive member, drill holdingmeans removably mounted onthe bed and having alternate upright and inverted positions forcontacting in turn the respective cutting faces of the drill with theabrasive member, a stop member on one of said base and guide means, anda rotatable member on the other of said base and guide means having aspiral cam surface adapted to engage the stop member, said rotatablemember comprising a feed control for said base in the upright positionof said drill holding means and a stop for said base in V the invertedposition of said drill holding means.

2. The apparatus of claim 1 wherein the drill holding means comprises anupright yoke member and screw means mounted in said yoke member forclamping said drill on said drill holding means, said base having arecessed portion disposed vertically below said yoke member forreceivingthe latter in the inverted position of said drill holding means;

3. Drill sharpening apparatus comprising an abrasive member, a base,guide means directed toward the abra sive member and mounting the basefor straight line feed movement toward said abrasive member, bedmeansmounted on the base at a predetermined angle with respect to theabrasive member, drill holding means removably mounted on the bedandhaving alternate upright and inverted positions for contacting in turnthe respective cutting faces of the drill with the abrasive member, anangular tab on the bed means engageable with the drill holding means forrestricting relative movement betweenthe drill holding means and the bedin one right position of said drill holding means and a stop for saidbase in the inverted position of said drill holding means, and meansconnected to the rotatable member for rotating the same.

References Cited in the file of this patent V UNITED STATES PATENTS1,576,311 Des Jardins Mar. 9, 1926 2,217,091 Zwick Oct.. 8, 19402,524,279 Van Wyk Oct. 3, 1950 2,580,884 Bowman Jan. 1, 1952.

